Small Animal Imaging (WUSAIR) Core The Washington University Small Animal Imaging Resource (WUSAIR) is one of the five original Small Animal Imaging Research Program (SAIRP) centers funded in 1999 and was competitively renewed in 2004. WUSAIR provides state-of-the-art facilities and infrastructure for MRI, PET, CT, SPECT and optical imaging of mice, rats and other small laboratory animals. Located in the heart of the Washington University Medical Center, WUSAIR combines instrumental and intellectual capabilities found at few other institutions. WUSAIR serves a broad community of cancer scientists, non-experts in MRI, CT, PET or optical technology, who have a pressing need for quantitative image analysis of small laboratory animal model systems. A particular focus is on mouse and rat models of cancer. WUSAIR also provides research and development at the frontier of imaging technology in an effort to make the most powerful new imaging strategies available to its community of users. WUSAIR imaging modalities are supported by the following operational instrumentation: microPET, microCT, nanoSpect, small animal 4.7 T and 11.74 T MRI, optical absorption, fluorescence, diffuse optical tomography (DOT) and bioluminescence in vivo imaging, and optical microscopy, through both commercial and custom built systems. See resources for a complete listing of instrumentation. The ancillary services and capabilities within WUSAIR include physics and engineering support for the development and design of new hardware and imaging methods;informatics support for local and remote data access, analysis, visualization and archival;new contrast-agent development;biostatistics consultation for experiment planning and data analysis;and animal procedure assistance for surgical procedures, catheter placement and maintenance, and monitoring of physiologic status during imaging experiments. WUSAIR will provide the NTR with comprehensive small-animal imaging resources for development of probes and pre-clinical evaluations and validation of imaging methods. WUSAIR also provides the potential for other members of the NTR-Networks to utilize comprehensive small-animal imaging resources. This will be of particular benefit to institutions lacking in one of the many imaging modalities represented by WUSAIR. Importantly, WUSAIR will help to facilitate new projects quickly and efficiently and thus is compatible with offsite investigators.